Edit Symfony template and added legacy in community

[fsoedjede]

Reasons for making this change:

I'm not directly linked to the Symfony project. I'm just a contributor.

This change is based on my experience when creating a new project. GitHub suggest choosing a .gitignore template. In my case, I was creating a Symfony 5 project but the template I got contains deprecated lines.

The change I'm proposing is to use Versioned templates for Symfony gitignore.

• Current version handled by existing gitignore: 2.x, 3.x, 4.x
• Current version of Symfony 5.x

What I did is:

1. Move the file Symfony.gitignore to community/PHP/Symfony4.gitignore

I chose only release which are LTS: https://symfony.com/releases

2. Add a file name Symfony.gitignore which contains only Symfony 5 related ignores.

Links to documentation supporting these rule changes:

• https://symfony.com/doc/5.4/reference/configuration/kernel.html#cache-directory

# Lines added
/var/cache/*
!var/cache/.gitkeep

• https://symfony.com/doc/5.4/reference/configuration/kernel.html#log-directory & https://symfony.com/doc/5.4/logging.html#where-logs-are-stored

# Lines added
/var/log/*
!var/log/.gitkeep

• https://symfony.com/doc/5.4/session.html#configuration

# Lines added
/var/sessions/*
!var/sessions/.gitkeep

• https://symfony.com/doc/5.4/configuration/secrets.html#configuration

# Lines added
/config/secrets/prod/prod.decrypt.private.php

• https://symfony.com/doc/5.4/configuration.html#overriding-environment-values-via-env-local

# Lines added
/.env.local
/.env.local.php
/.env.*.local

• https://symfony.com/doc/5.4/testing.html

# Lines added
.phpunit.result.cache
/phpunit.xml
/phpunit.xml.dist

• https://symfony.com/doc/5.4/frontend/encore/installation.html

# Lines added due to Node.js usage
/node_modules/
npm-debug.log
yarn-error.log

If this is a new template:

• Link to application or project’s homepage: https://symfony.com

[vinceAmstoutz]

@Github Please can you process this request because Symfony's gitignore is outdated (LTS is curently in v.5 not v.4) !